@mixin hairline-common() { content: ' '; position: absolute; border-width: 0; border-style: solid; border-color: inherit; border-radius: inherit; pointer-events: none; box-sizing: border-box; } @mixin hairline() { @include hairline-common(); width: 200%; height: 200%; left: 0; top: 0; transform: scale(0.5); transform-origin: 0 0; } @mixin hairline-top($left: 0, $right: 0) { @include hairline-common(); left: $left; right: $right; top: 0; border-top-width: 1px; transform: scaleY(0.5); } @mixin hairline-bottom($left: 0, $right: 0) { @include hairline-common(); left: $left; right: $right; bottom: 0; border-bottom-width: 1px; transform: scaleY(0.5); }